A student plays an online game using a laptop connected to the school Wi-Fi.
Explain one reason why an online game can respond more slowly over a wireless connection than over a wired connection.
Mark scheme
Award up to two marks for a linked explanation such as:
- Wireless signals can be blocked or absorbed by walls (1) so the data must be re-sent, which adds delay (1)
- A device further from the access point has a weaker signal (1) so data must be re-sent/transmitted at a lower rate, adding delay (1)
- Devices on a wireless network share a channel (1) so a device must wait its turn to transmit, which adds delay (1)
- Interference from other devices affects the radio signal (1) so data must be re-sent, adding delay (1)
For both marks, the expansion must follow/associate with the statement.
Allow 'waiting to send' or 'collisions' as the delay caused by devices sharing a channel.
Do not accept 'wireless is slower than wired' on its own, as this repeats the question.
Do not accept a reason that only affects download speed/bandwidth (e.g. 'files take longer to download') without a link to delay.
Example answers and how they were marked
Interference from other devices affects the radio signal, so the data has to be re-sent and this adds delay before the player's action appears.
Why: Linked point (1): interference affects the signal; reason (1): re-sending the data adds delay (latency).
Walls can block the wireless signal.
Why: Point only (1): walls block the signal. No linked reason saying that this means data must be re-sent, which adds delay.
Wireless has less bandwidth than wired, so a game update takes longer to download.
Why: Confuses latency with bandwidth/download speed; the mark scheme says not to accept this without a link to delay.